The prior art has many disconnection knifes in the form of a round or rectangular bar, where the contact surfaces in their entirety are planar, including between them the rounded curves, but planar at the end, and they do not have reference parameters with the contact pressure between the surfaces involved; being ineffective in the removal of oxides and general cleaning during the movement of connection and disconnection. There are parallel knifes with copper bar that exert a contact pressure on plane surfaces, said pressure being provided by means of springs mounted on the screw that joins the bars; but the circulation of current is allowed across this spring, and in doing so it becomes heated, with the consequent loss of tension upon changing its elastic limit, and then the contact pressure is lost with use, consequently generating micro-arcs and heating the bars until they melt.
One of the common recurring faults in the distribution substations is the sudden opening of the power breakers due primarily to overheating of the live parts of said breakers. This situation leads to the suspension of the electrical supply service, causing substantial losses to the users. The faults are due primarily to the generating of micro-arcs by wrong contact, which ultimately lead to the creation of a complete arc that melts the metal of the contact bar and interrupts the supply of electricity.
It is thus necessary to provide a device that is capable of maintaining the load levels, with operating capability above the current specifications, that can withstand greater loads without causing overheating and with a simple design that avoids the use of a large number of parts that are hard to assemble, in that special tools are required.
The disconnector of Japanese patent JP 2006351397, published on 28 Dec. 2006, whose inventor is Sasaki Toshiaki, describes a turning mechanism provided with a vertical actuator bar, coated with insulator; a horizontal bar is fixed onto the insulator and it can turn along with the vertical actuator bar; in turning, it connects or disconnects the electrical energy at the upper ends of the outermost insulators.
The disconnector system of Japanese patent JP 2005285534, published on 13 Oct. 2005, whose inventor is Uchida Yasushi, describes a plurality of monopolar disconnectors provided with a horizontal turn bar supported on a central insulator that causes the disconnection bar to turn, connecting or disconnecting the electrical energy at the upper ends of the insulators receiving and transmitting the energy, said insulators being fixed to a lower horizontal base. The central insulator is made to turn by means of an actuator bar.
Japanese patent JP 11120870, published on 30 Apr. 1999, whose inventor is Okamoto Tamotsu, describes a rotating disconnection knife with two contact ends that are coupled to two axial U-shaped fingers in horizontal position, said fingers being contained one inside the other. The knife is fixed to a rotating insulator and at the lateral ends it has contact surfaces in the form of a loop that enter into the flat surface finger of horizontal U-shape to close or open the circuit of electrical energy coming from the transformer.
Russian patent RU 2127006 published on 27 Feb. 1999, whose inventor is Konopel Kov et al., describes a disconnection switch provided with a frame together with one fixed insulator and another one that can turn; it also has a lever-type control mechanism. The current collector has two parallel contact knifes fastened by means of bushings, the ends of the knifes having springs that provide contact pressure.
Japanese patent JP 10079216 published on 24 Mar. 1998, whose inventor is Ito Hitoshi, describes a disconnection mechanism that consists of two fixed outside insulators and two middle insulators that can turn, provided with a knife section in the upper end, which are coupled together by means of the turning of the outermost insulators, thereby allowing or interrupting the flow of current through the outermost insulators.
The U.S. Pat. No. 4,112,268, published on 5 Sep. 1978, whose inventor is Chung Asunción, describes a disconnection knife that consists of a horizontal base on which are located two fixed outside insulators and one middle insulator which can turn, having at its upper end a knife or horizontal bar at whose ends it has a contact jaw that couples at each upper end of the fixed insulators, the coupling occurring at low pressure to enable an easy disconnection.
The U.S. Pat. No. 3,230,324 published on 18 Jan. 1966, whose inventor is Tomlinson F. Johnson, describes a quick disconnection switch for high voltage, in the switch two outside support insulators are connected by means of a base bar and in the body of same an interruption element in each of the insulators, of these disconnection elements one moves in the clockwise direction and the other counterclockwise to disconnect the flow of high-voltage current, the movement taking place by means of an intermediate mechanism between the ends of the disconnection elements.
The U.S. Pat. No. 3,004,117, published on 10 Oct. 1961, whose inventor is John W. Skooglund, describes a disconnection switch for high voltage provided with a base that has a pair of insulators at each end, at the upper edge of one pair of these is situated the fastening base for a disconnection bar that can turn in the vertical plane, on the insulator closest to the opposite pair is placed a mechanism for coupling, securing and releasing of the bar when it is in the horizontal connection position.
The U.S. Pat. No. 2,816,971, published on 17 Dec. 1957, whose inventor is Payton C. Mayo et al., describes a disconnection bar that turns on its base in the vertical plane to be coupled by gravity in the upper end of the insulator where the contact finger is located.
The British patent GB 718,343, published on 10 Nov. 1954, whose inventor is Joseph Daniel Hoffman et al., describes an arrangement of electrical contacts for disconnection switches with a tubular vertical knife that has a pressing mechanism provided by an internal spring against a contact roller on an inclined plane of a fixed flange that has a shoulder to prevent the deliberate disconnection of the vertical knife; in its middle section the knife has a contact element coated with silver to increase the conductivity; the device has mechanical means to adjust the knife relative to its contact surface and support.
The British patent GB 673,598, published on 11 Jun. 1952, describes a disconnection device for high-voltage circuits with a disconnection arm operated by an insulating lever that opens or closes the circuit to interrupt or allow the flow of current.
The British patent GB 643,953, published on 27 Sep. 1950, describes a disconnection switch for high voltage that provides protection against deterioration caused by the corrosiveness of the environment, such as the buildup of frost and dust and the corrosion caused by this; the mechanism comprises a knife with two degrees of freedom or double throw, making contact with high pressure, consisting of four insulators arranged in the shape of a cross, one at the supply post, the one fastening the knife at the center, and two connection ones at the opposite ends of the arms; the knife is disconnected from one of these when performing cleaning and repair work, while being connected at the opposite side; the base of the knife has a closed protection housing that protects it against frost or dust buildup from the surroundings; the knife turns in the vertical plane, making contact against planar surfaces.
Given the above, there is a need to provide a disconnection knife with safe and efficient performance that does not cause overheating on its live parts, while conducting the current across them, being made of electrolytic copper with low resistance.